As a Brewtus owner I feel fortunate with the greater simplicity of flushing out water which has been sitting and staling but having to visit (single boiler) machines owned by others to see the whole routine in action.

Question though, what happens with commercial machines in use en masse in the high street the world over? Do they work differently or do they need a cooling flush because many operators don't do this when preparing your mate's drink (I'm assuming most of us order tea if anything when we're out and about :-) )